1. Field of the Invention
The present general inventive concept relates to encoding and/or decoding a wideband signal, and more particularly, to a method and an apparatus to encode and/or decode a high frequency band signal using a low frequency band signal.
2. Description of the Related Art
According to ITU-T G.772.2 recommendation (hereinafter, the “G.772.2 specification”), which is widely followed in the field of speech transmission, 16 kHZ wideband speech signals are down-sampled to 12.9 kHz and then encoded to reduce the number of bits used for representing the input signals. The encoders in a G.772.2 compliant system perform linear predictions that do not allocate bits to encode voice information spectrally located in high frequency bands.
Accordingly, decoders use comfort noises to perform up-sampling so as to generate high frequency bands that were excluded through down-sampling at the encoder. However, these signals are artificially generated by the decoders and do not correspond to the high frequency components of the original signals. Thus, a spectral envelope different from the envelope of the original signal is generated. As a result, the quality of the reproduced speech is diminished.